There are two different types of access networks for packet data transmission. These are shown in FIGS. 1 and 2. FIG. 1 shows a typical Ethernet passive optical network (EPON) consisting of an optical line terminal (OLT) 10 at the headend side of the system. A typical OLT has medium access logic 12 connected to transmitter (Tx) 14 and receiver (Rx) 16 that is connected to wavelength division multiplexer (WDM) 18. The data packets are sent and received through optical fiber 20. Optical fiber 20 is connected to 1:N optical splitter 22 which is dispersed to a plurality of optical network units (ONUs) 24 on the customer premises side.
A second type of access network is shown in FIG. 2. This is a coaxial cable-based access network. In this system access network controller 26 at the headend side, is linked by coaxial cable 28 to a plurality of coax networks units (CNUs) 30 at the customer premises side.